How to draw a symmetrical triquetra with an equilateral triangle

[@DisStudioDesigns]

Accompanying blog posts for this tutorial:
disstudiodesigns.com/blog/how-to-draw-a-celtic-triquetra-using-an-equilateral-triangle
disstudiodesigns.com/blog/how-to-draw-a-triquetra-using-a-right-angle-triangle
disstudiodesigns.com/blog/how-to-draw-a-simple-celtic-triquetra-using-three-circles